Symbiotic Relationships
Commensalism
Explain how commensalism is a symbiotic relationship and give an example
Why does a typical ecostystem have many more plants than herbivores? Where are the plants in an energy pyramid?
Read on to the next blog for more science review.
The science test is MONDAY!
Fill in the blank (10)
adaptation, ecosystem, food chain, habitat, limiting factor, mimicry, niche, population, protective coloration, symbiosis
Know these terms
producer-herbivores-carnivores-decomposers-omnivores
food chains, carrying capacity, mutualism, commensalism, parasitism, mimicry, camouflage and adaptation
Abiotic and Biotic Factor-List
Read Graph and Interpret Data Structural and Behavior Adaptations
Habitat and Niches
Predator and Prey
Simple Machines
This week we are researching simple machines (thanks to the ipads). Next week, the students will be designing and building an obstacle course using 6 simple machines.
Fifth grade science should expect their chapter test on Monday. This test covers Chapter 3 Lessons 1-2-3.
Homework Notice for Science
It is the responsibility of the student to obtain a homework slip if their homework is not completed for the day that it is due. If the notice and the homework are returned the following day (with parent signature) then 50% credit will be given to the final grade of the assignment.
If the student fails to obtain a homework slip, then no credit will be issued. It is the responsibility of the student to obtain the homework slip. Graded assignments are returned to the class the following class day so no credit can be obtained.
Magic Rollback Can - Sick Science!
Potential and kinetic energy at work in this magical demonstration
(2 Reviews)
In our long line of "magical" science, we introduce the Magic Rollback Can. The Magic Rollback Can appears to be a normal can of coffee or oats, but after you roll it along the ground a little ways and watch it come back, you'll be wondering just how it works.
Email Materials
Coffee or oats can
Nail or other hard pointed object
9-volt battery or object with similar weight
Rubber band
2 paperclips
Tape
Experiment Video Related Experiments Reviews
Using the nail, make a hole in the middle of the bottom of your coffee or oats can. Be extra careful when using sharp objects. Also, if you are using a coffee can, be careful around the sharp metal edges that you may create when making the hole.
Poke the same kind of hole in the lid of the can.
Tape the 9-volt battery to the middle of the rubber band. Make sure both sides of the rubber band are taped to the bottom of the battery.
Push one end of your rubber band loop through the hole in the bottom of the can and secure it there by attaching one of the paperclips. Once you have it secured, tape the paperclip down.
Stretch the rubber band across the length of the can and push the other end of the rubber band loop through the hole in the lid.
Secure the rubber band with a paperclip and tape it down.
Put the lid on the can. Does the battery rub against the side of the can? If not, you're good to go. If it does, try a shorter rubber band.
Getting the set-up just right may take a bit of experimentation, but you'll get it!
Set the can on its side on a hard surface or short carpet floor and give it a roll. Once the can comes to a stop, try to contain your excitement as it begins to roll back to you!
How does it work?
The Magic Rollback Can is a great example of transfer of energy. When you roll the can, it has kinetic energy. As it slows down, the energy is transferred into potential energy within the twisted rubber band inside the can. The twisted rubber band's potential energy is then transferred back to the can in kinetic energy as it untwists.
The secret to all this energy transfer comes from the weight that you've taped to the rubber band inside the can. While the weight is being pulled down by gravity, it is also being subjected to a twisting force from the rubber band. So long as the force being exerted by gravity on the weight is greater than the twisting rubber band's force on the weight (meaning the weight never goes over the rubber band), the rubber band will continue to twist.
Once all of the kinetic energy from the rolling can has been exhausted by converting to heat (friction) or potential energy (twisted rubber band), the can stops rolling and the weighted rubber band is able to unwind. Because of the weight in the middle of the rubber band, only the ends of the loop are able to unwind and, therefore, the can begins to roll backwards.
Additional Info
If you are looking to take the Magic Rollback Can to the next level, try painting it a solid color. If you do this, observers won't be able to see the apparatus on the ends of the can. This makes the Magic Rollback Can a perfect "Black Box" tool for teachers. Show your students what the Magic Rollback Can does, and have them observe and hypothesize how the can might work.
Chapter 11 Lesson 2 test tomorrow. A review guide was given along with the essay questions. Students may bring a notecard with the formulas for finding mass, acceleration and force. Calculators may be used for the test, also.
Enjoy the three day weekend!
Changes in Motion Chapter 11 Lesson 2
1. An object's acceleration equals the net force on the object divided by its _______________.
2. According to Newton's second law of motion, acceleration depends on the object's mass and the amount of ____________________ applied to it.
3. If the force increases, then the acceleration __________________;if the mass increases, then the acceleration _________________.
4. Newton's first law of motion shows that a net force is needed in order for an object to _______________________.
5. Newton's ______________law of motion shows how much acceleration a net force will cause.
6. Momentum measures the mass and _____________ of an object.
7. According to the principle of _________________________________________________, total momentum does not change when objects collide.
8. If two balls are moving at the same speed, the ball with greater mass will be _______________________ to stop.
Next Wednesday, will be our last class before our Christmas vacation. It is a little tradition that I bring breakfast in for the kids. A note went home about a gift exchange for that day. It is optional but a fun activity. Thanks.
1. Explain the term inertia.
2. The greater the _________ the greater the acceleration. The larger the ________
of the object the greater the force required to accelerated or slow down the object.
3. What is Newton's third law of motion?
4. What force makes us move forward when a car suddenly stops?
5. Name some ways (2 ways) that friction can be helpful and some wasy it is harmful (2 ways).
6. What force holds an object in a circular orbit?
7. Why is it harder to stop a train than a car when the car is moving faster?
8. Describe how mass and weight are different.
9. A spacecraft traveling in space can travel at a constant speed and in a straight path without using engines. Why?
10. How is momentum calculated?
