I need a good science project for 6th graders?

Question

it has to by why somthing does this or how somthing lik temperature affects anoter object

Answer 1

Viscosity
Show Viscosity (flow resistance) by using several liquids. You can also show how heat and ice effect the flow of these fluids. For example: Have 4 jars with lids and label them with the fluid. ..honey, water, veggie oil and regular auto oil (used is better). They all flow at different rate which you can show visibly by turning each jar. (I might not use honey ...it will be the worst mess.to clean up.)
Also put all 4 fluids in one jar and let it sit and watch what happens. You will have to do some more research on this but it is an easy visual project where you can see the different viscosity of each.
Viscosity is a measure of the resistance of a fluid to deform under shear stress. It is commonly perceived as "thickness", or resistance to pouring. Viscosity describes a fluid's internal resistance to flow and may be thought of as a measure of fluid friction. Thus, water is "thin", having a lower viscosity, while vegetable oil is "thick" having a higher viscosity. All real fluids (except super fluids) have some resistance to shear stress, but a fluid which has no resistance to shear stress is known as an ideal fluid or inviscid fluid (Symon 1971).

Answer 2

I assume you mean a hands-on project for the kids and not a classroom demonstration performed by the teacher (you?). This really limits the choices because, of course, it must be perfectly safe for the kids. No poisons, no fire, no electricity, no knives, no explosions, no nothing. ( I also imagine you've got nearly no budget.)

Get some wooden sticks, about 1"x10"x1/8" One stick for each team of kids. Have the kids use a metric scale to find and mark the exact center of their stick. Next, they'll mark and label each centimeter, starting from the center and working out to both ends. You'll need to dream-up a fulcrum (triangular wooden block) for each team. Have the kids adjust each of their sticks with bits of masking tape until the sticks balance at their centerlines. Only then do you provide each team with ten 5-cent coins. (Honesty check?) The kids should think of the nickels as 5-gram weights (They're very close.) Have the kids experiment by placing one or more weights on each side and trial and error until they get a balance. For example, 10 grams at 10-cm to the right will exactly balance 20 grams at 5-cm to the left. Let them play around for quite awhile and record all the combinations they can discover that balance. Collect all the nickels, sticks and fulcrums. Now you lead a classroom discussion "searching" for a general principle. How exactly does a balanced condition occur? Lead them to the discovery that only when the product of weight times distance is equal on both sides do you get a balance. 100gm-cm is the same amount of torque whether it comes from 5g x 20cm, or from 10g x 10cm, or from 20g x 5cm.

Hope you find this suggestion useful................